The present invention relates generally to particle blast systems, and is particularly directed to a device which provides improved introduction of particles into a transport gas flow for ultimate delivery as entrained particles to a workpiece or other target. The invention will be specifically disclosed in connection with a cryogenic particle blast system which introduces particles from a pressurized container via a feeder without an airlock between the container and the discharge station.
Particle blasting systems have been around for several decades. Typically, particles, also known as blast media, are fed into a transport gas flow and are transported as entrained particles to a blast nozzle, from which the particles exit, being directed toward a workpiece or other target.
Carbon dioxide blasting systems are well known, and along with various associated component parts, are shown in U.S. Pat. Nos. 4,744,181, 4,843,770, 4,947,592, 5,018,667, 5,050,805, 5,071,289, 5,109,636, 5,188,151, 5,203,794, 5,249,426, 5,288,028, 5,301,509, 5,473,903, 5,520,572, 5,571,335, 5,660,580, 5,795,214, 6,024,304, 6,042,458, 6,346,035, 6,447,377, 6,695,679, 6,695,685, and 6,824,450, all of which are incorporated herein by reference.
Many prior art blasting system, such as disclosed therein, include rotating rotors which form an air lock, sealing between the hopper which holds the pellets and the flow of pressurized transport gas into which the particles are entrained and carried to the workpiece. Other prior art blasting systems utilize suction created by a Venturi nozzle typically located at the blasting gun usually requiring a two hose system. The present invention does not require the use of an airlock or a Venturi nozzle.
Although the present invention will be described herein in connection with a particle feeder for use with carbon dioxide blasting, it will be understood that the present invention is not limited in use or application to carbon dioxide blasting. The teachings of the present invention may be used in applications using any suitable type or size of particle blast media.
Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.